#define _CRT_SECURE_NO_WARNINGS 
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
const int N = 2010;
ll a[N],maxx;
int main()
{
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++)
	{
		cin >> a[i];
		maxx = max(maxx, a[i]);
	}
	for (int i = 1; i <= n; i++)
	{
		ll ans = a[i];
		for (int j = i + 1; j <= n; j++)
		{
			ans = ans ^ a[j];
			maxx = max(maxx, ans);
		}
	}
	cout << maxx << endl;
	return 0;
}